On the Spectral Properties of Selfadjoint Partial Integral Operators with a Nondegenerate Kernel

IF 0.7 4区 数学 Q2 MATHEMATICS Siberian Mathematical Journal Pub Date : 2024-03-01 DOI:10.1134/s0037446624020204
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Abstract

We consider bounded selfadjoint linear integral operators  \( T_{1} \) and  \( T_{2} \) in the Hilbert space \( L_{2}([a,b]\times[c,d]) \) which are usually called partial integral operators. We assume that  \( T_{1} \) acts on a function  \( f(x,y) \) in the first argument and performs integration in  \( x \) , while  \( T_{2} \) acts on  \( f(x,y) \) in the second argument and performs integration in  \( y \) . We assume further that  \( T_{1} \) and  \( T_{2} \) are bounded but not compact, whereas  \( T_{1}T_{2} \) is compact and \( T_{1}T_{2}=T_{2}T_{1} \) . Partial integral operators arise in various areas of mechanics, the theory of integro-differential equations, and the theory of Schrödinger operators. We study the spectral properties of  \( T_{1} \) , \( T_{2} \) , and \( T_{1}+T_{2} \) with nondegenerate kernels and established some formula for the essential spectra of  \( T_{1} \) and  \( T_{2} \) . Furthermore, we demonstrate that the discrete spectra of  \( T_{1} \) and  \( T_{2} \) are empty, and prove a theorem on the structure of the essential spectrum of  \( T_{1}+T_{2} \) . Also, under study is the problem of existence of countably many eigenvalues in the discrete spectrum of  \( T_{1}+T_{2} \) .

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论具有非enerate 内核的自兼偏积分算子的谱特性
Abstract 我们考虑希尔伯特空间 \( L_{2}([a,b]\times[c,d]) \)中的有界自交线性积分算子 \( T_{1} \)和 \( T_{2} \),它们通常被称为部分积分算子。我们假设 \( T_{1} \) 作用于函数 \( f(x,y) \) 的第一个参数并在\( x \) 中执行积分,而 \( T_{2} \) 作用于函数 \( f(x,y) \) 的第二个参数并在\( y \) 中执行积分。我们进一步假设 \( T_{1} \) 和 \( T_{2} \) 有界但不紧凑,而 \( T_{1}T_{2} \) 紧凑且 \( T_{1}T_{2}=T_{2}T_{1} \) 。偏积分算子出现在力学、积分微分方程理论和薛定谔算子理论等多个领域。我们研究了 \( T_{1} \) , \( T_{2} \) , 和 \( T_{1}+T_{2} \) 的谱性质,并建立了 \( T_{1} \) 和 \( T_{2} \) 的本质谱公式。此外,我们证明了 \( T_{1} \) 和 \( T_{2} \) 的离散谱是空的,并证明了 \( T_{1}+T_{2} \) 的本质谱结构定理。此外,我们还研究了 \( T_{1}+T_{2} \) 的离散谱中存在可数个特征值的问题。
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来源期刊
CiteScore
1.00
自引率
20.00%
发文量
88
审稿时长
4-8 weeks
期刊介绍: Siberian Mathematical Journal is journal published in collaboration with the Sobolev Institute of Mathematics in Novosibirsk. The journal publishes the results of studies in various branches of mathematics.
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